Fork Notesium source and restructure into Go package layout

Initial fork of github.com/alonswartz/notesium into librenotes:
- Source moved to internal/notesium/ (package notesium)
- Thin entry point at cmd/librenotes/main.go
- Module renamed to git.librete.ch/public/librenotes
- main() exposed as notesium.Run()
- LICENSE preserved (MIT), NOTICE added with attribution
- Web assets and completion.bash co-located with embedding code
  to satisfy go:embed path constraints

Closes #3, #34, #35.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/notesium/web/app/settings-keybinds.js

@@ -0,0 +1,65 @@
+var t = `
+<div class="h-full w-full overflow-y-scroll pb-6">
+  <div class="relative flex-1 px-6 mt-2 space-y-6">
+    <div v-for="section in sections" :key="section.name" class="rounded-md border border-gray-200">
+      <div class="pl-6 py-2 bg-gray-100 border-b border-gray-200 items-center justify-items-center">
+        <span class="text-xs font-semibold leading-6 text-gray-900" v-text="section.title"></span>
+      </div>
+      <div class="divide-y divide-gray-100 w-full">
+        <div v-for="entry in section.entries" class="w-full flex px-6 py-2 text-xs items-center justify-items-center justify-between">
+          <div class="flex">
+            <span v-if="entry[2]" class="text-gray-600 font-medium w-20 mt-1" v-text="entry[2]"></span>
+            <span class="text-gray-900 font-medium mt-1" v-text="entry[1]"></span>
+          </div>
+          <span class="text-gray-900 font-mono bg-gray-200 rounded-md p-2 pb-1" v-text="entry[0]"></span>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+`
+
+export default {
+  data() {
+    return {
+      sections: [
+        {
+          name: 'global',
+          title: 'Global',
+          entries: [
+            ['space n n', 'Open new note for editing'],
+            ['space n d', 'Open new or existing daily note'],
+            ['space n w', 'Open new or existing weekly note'],
+            ['space n l', 'Finder: List with prefixed label, sorted alphabetically'],
+            ['space n c', 'Finder: List with prefixed date created, sorted by ctime'],
+            ['space n m', 'Finder: List with prefixed date modified, sorted by mtime'],
+            ['space n k', 'Finder: Links related notes to active note (or all if none open)'],
+            ['space n s', 'Finder: Full text search across all notes'],
+            ['space n g', 'Open fullscreen force graph view'],
+          ]
+        },
+        {
+          name: 'finder',
+          title: 'Finder',
+          entries: [
+            ['C-p', 'Toggle preview'],
+            ['↓ | C-j', 'Select next entry (down)'],
+            ['↑ | C-k', 'Select previous entry (up)'],
+            ['Enter', 'Submit selected entry'],
+            ['Esc', 'Dismiss finder'],
+          ]
+        },
+        {
+          name: 'tabs',
+          title: 'Note tabs',
+          entries: [
+            ['C-h', 'Switch to note tab on the left of the active note tab'],
+            ['C-l', 'Switch to note tab on the right of the active note tab'],
+            ['C-^ | C-6', 'Switch to previously active tab'],
+          ]
+        },
+      ],
+    }
+  },
+  template: t
+}